Caulkless panelized wall system

ABSTRACT

Disclosed herein are caulkless panelized wall systems and methods for their construction, wherein the wall systems have elastomeric joints that are resistant to cracking. Building panels are fastened to a frame with the edges adjacent to each other. No caulk is applied to the seam between the building panels. A backing material is applied over the seam between the panels and the wall is then finished with an elastomeric finish.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 60/333,967, filed Nov. 28, 2001, U.S. Provisional PatentApplication Ser. No. 60/334,138, filed Nov. 28, 2001, and U.S.Provisional Patent Application Ser. No. 60/334,144, filed Nov. 28, 2001,the disclosures of which are incorporated by reference in theirentireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present application relates generally to walls made with buildingpanels, and more particularly, to caulkless panelized wall systems withjoints that are resistant to cracking.

2. Description of the Related Art

Every building tradition in the history of mankind has producedstuccowork. Examples of stuccowork range from the Aztec architecture ofancient Mexico to the architecture of North Africa and Spain. In moderntimes, stuccowork has been popular in residential construction since the1920s, especially in dry, warm climates like the U.S. Southwest. Becauseof the many ways in which it can be treated, stucco remains a popularexterior finish for many building types. Since stucco is applied as apaste, it can be textured and will conform to almost any shape resultingin a smooth, seamless wall of monolithic appearance and sound structuralintegrity.

In spite of its ongoing popularity, many builders resist using stucco asan exterior finish in framed construction because of the problemsassociated with applying stucco to exterior walls. Traditionally, astucco coating is a thin paste composed of Portland cement, sand, lime,and water. Successive layers of stucco paste are applied to a metal orplastic mesh fastened to the exterior of the wall. Stucco supported onframed construction is normally ⅞″ thick and is applied in threeapplications: the first or scratch coat, the second or brown coat, andthe third, a finish, colored, texture coating. Since each layer ofstucco paste must dry and harden before the next is applied, it takesseveral days to finish a traditional stucco wall.

While hundreds of thousands of new housing units are built every year,only a fraction of those units use stucco as an exterior finish.Stucco's susceptibility to moisture damage, for example, limits its usein wet climates. Likewise, stresses caused by transportingstucco-finished transportable buildings prevent its use in the lucrativemanufactured housing market.

Another method of producing a textured or stucco look is aDirect-applied Exterior Finish System or DEFS. In DEFS, panels of asubstrate material are fastened to the framing followed by a finishtexture coating. The texture coating may be applied as a single coat orin multiple thin coats, and often uses either a joint or full-wrapalkali-resistant fiberglass mesh to reinforce the coating againstcracking. DEFS can be installed and finished in a much shorter time thantraditional stucco, enabling shorter construction times.

DEFS have not enjoyed a large share of the exterior market, however,because thin DEFS coatings, which are relatively brittle, areincompatible with the movements of wall panels. The substrate panelswill invariably move with respect to each other from building settling,temperature variations, or moisture absorption. These movements cancause cracking of the finish at the panel joints. To prevent thiscracking, the joints are often covered with tape or filled with caulk.In many installations, both tape and caulk are used. In DEFS stuccoapplications over fiber cement, an alkali-resistant fiberglass meshtape, 2″ to 12″ wide, joins the two adjacent fiber cement panels thatare the substrate over which the stucco is applied.

One problem with these types of joints is “joint read,” a phenomenon inwhich the joint underlying the finish is visible. Joint read breaks thedesired monolithic appearance of the finished wall. Joint read is aparticular problem with fiber cement substrates becausefiber-cement-panel faces absorb moisture from the finish coat fasterthan the taped joint. This differential moisture absorption makes thejoint visible. In joints covered with tape, the step formed by the edgeof the tape and the panel surface can often be seen, especially withlow-angle illumination. Cracks arising from the loss of adhesion orslipping at the edges of the tape cause another type of joint read.

“Peaking” is another type of joint read and is caused by movement of thefiber cement panels. This movement causes the adhesive bond between thejoint tape and the caulk joint to fail, causing the stucco to separatefrom the caulk. As a result, the stucco covering the joint floats higheror lower than the surrounding area, giving the appearance of a peak.Peaking also results from the caulk shrinking during curing, pulling theadhered joint tape below the surface of the stucco. Peaking disrupts themonolithic appearance of the wall and destroys the integrity of both thestucco and the substrate.

Another option is a thin joint sealing tape. These tapes, however, areoften waterproof. Consequently, they do not absorb the stucco mix,resulting in poor adhesion between the stucco and the tape, which leadsto surface deformation.

A more serious problem is cracking at the joints. Cracking not onlydisrupts the monolithic look of the finish, but also allows moisture toget behind the stucco and rot or corrode the wood or steel structuralframing. Furthermore, these cracks are entry points for insects orfungi, which can damage the interior of the wall.

Consequently, DEFS are rarely used where there is wide daily temperaturevariation especially when coupled with a high rate of wet/dry cycling.DEFS are also seldom used in the fast-growing manufactured housingmarket because of the additional stress placed on walls duringtransport. Solving the joint read and stucco-cracking problems couldsignificantly expand the market for DEFS stucco applications using fibercement and other substrates. Not only could builders use fiber cementsubstrates and stucco in wetter climates, but also fiber cementsubstrates and stucco use could be expanded to new markets such asmanufactured housing and modular buildings.

One strategy for preventing cracking of a DEFS coating at the paneljoints is to construct joints from elastomeric materials. Theseelastomeric joints absorb the stress created by the differential panelmovements. Such joints may be used with flexible, latex-based texturecoatings, often called latex stucco or synthetic stucco. These finishesare able to move with the joint without cracking, which would greatlyexpand the market for DEFS applications.

The effectiveness of such joints may be evaluated in test wallsconsisting of several panels assembled on a frame, constructed with thejoint-to-be-tested. The test wall is finished with a DEFS coating andsubjected to a racking test. The racking test applies an in-plane shearforce to the test wall, resulting in relative panel movement, until theDEFS coating cracks. The distance of maximum deflection at which thefinish cracks is a measure of performance of the panel joints. Forexample, in order to pass the International Congress of BuildingOfficials (ICBO) AC 59 “Acceptance Criteria for Direct-Applied FinishingSystems” (September 1992), a test wall constructed according to themethod described in ASTM E-72 (98) subjected to a racking load thatcauses the wall to deflect 1″, does not develop any visible jointcracks.

The polymeric adhesives used in joint tapes in DEFS tend to soften andlose holding power at 120° F., a temperature often achieved on theexterior vertical walls of a building exposed to full summer sun. Fibercement building panels may become saturated with water in wetenvironments if installed improperly or if the finish layer fails. Manyadhesives bond poorly to wet substrates. The performance of adhesivesused in manufacturing joint tapes for DEFS applications may be evaluatedusing the “180° peel test,” a well-known method of evaluating theadhesive strengths of tapes. The 180° peel test measures the forcerequired to break the adhesion of a joint tape applied to two substratesheld at a 180° angle.

U.S. Pat. No. 5,732,520 describes a method for forming a single-coat,synthetic-stucco-finished exterior wall. First, fiber cement wallboardpanels are installed onto a building frame with the adjacent edges ofthe panels forming narrow gaps. Polyurethane caulk is applied to thegaps, and low-profile fabric-backed joint tape is applied over theadjacent edges of the panels to cover the gaps and the caulk. A highbuild flexible resinous latex emulsion in next applied directly over thepanels and adhesive tape to form a synthetic stucco finish. The moistureabsorption properties of the fabric from which the tape is manufacturedmatches that of the wall panels. A stucco-finished joint constructedaccording to this patent with 3″-wide joint tape slips and cracks at theedges when stretched 3–5 mm. The relative motion of adjacent 4′×8′cementitious boards under normal conditions is greater than 3–5 mm,however. While the joint tape described in U.S. Pat. No. 5,732,520distributes the joint movement somewhat, the adhesive used in this tapeis not sufficiently strong to prevent the edges of tape from slippingunder stress. Consequently, the edges of the tape slip, cracking thestucco coating. A wider tape, for example, a 6″-wide tape, might betterwithstand the movement, but at an increased cost.

Cracking may be also prevented by applying additional layers of stuccoor a joint compound over the tape before applying the final coat ofstucco. This method, however, is expensive, time consuming, and requiresskilled workers. Moreover, this technique often fails to producesatisfactory results. Another method of preventing cracks is increasingthe thickness of the stucco build. This method is also expensive andtime consuming, however.

SUMMARY OF THE INVENTION

The present disclosure provides panelized wall systems constructed withand without caulk and methods of their manufacture. The disclosedpanelized wall systems have elastomeric joints that are resistant tocracking.

Accordingly, a one embodiment provides a method of constructing apanelized wall system, with at least the steps of: positioning at leasttwo building panels over a frame, wherein each panel comprises a frontsurface, a back surface, and a plurality of edges, the back surfaces ofthe panels are positioned over the frame, and the two panels arepositioned adjacent to each other, forming a seam between the adjacentpanels; fastening the panels to the frame; and forming a caulklesselastomeric joint comprising a backing material adhered over the seam,wherein the backing material is adhered to the front surfaces of theadjacent panels without any caulk applied to the seam between theadjacent panels.

In a preferred embodiment, the panels are fiber cement.

In a preferred embodiment, the adjacent panels are positioned with nogap between them. In another preferred embodiment, the adjacent panelsare positioned with a gap between them. Preferably, the gap is about ⅛″wide.

In a preferred embodiment, the backing material is a fabric. Preferably,the backing material is from about 0.0005″ to about 0.04″ thick. Thefabric is preferably a non-woven polyester fabric or a polyamide mesh.Preferably, the backing material is about 3″ wide.

In a preferred embodiment, the backing material is applied as a jointtape, wherein the joint tape comprises an adhesive preapplied to a faceof the backing material.

In a preferred embodiment, the caulkless elastomeric joint furthercomprises a ceramic putty applied over the backing material. In anotherpreferred embodiment, the caulkless elastomeric joint further comprisesan elastomeric joint filler applies over the ceramic putty.

In an preferred embodiment, an elastomeric finish is applied to thepanelized wall system. Preferably, the elastomeric finish comprises anelastomeric primer and an elastomeric texture layer, or is a texturecoating.

In a preferred embodiment, the frame is a wood frame. In a preferredembodiment, the frame comprises shear panels. In a preferred embodiment,the frame comprises a moisture barrier. In a preferred embodiment, theframe comprises a water break.

Another embodiment provides a panelized wall system comprising: a frame;at least two building panels positioned over the frame, wherein eachpanel comprises a front surface, a back surface, and a plurality ofedges, the back surfaces of the panels are positioned over the frame,the two panels are positioned adjacent to each other, forming a seambetween the adjacent panels with no caulk applied to the seam, thepanels are fastened to the frame, and no caulk is applied to the seam;and a caulkless elastomeric joint comprising a backing material adheredover the seam between the adjacent panels, wherein the backing materialis adhered to the front surfaces of the adjacent panels without anycaulk applied to the seam between the adjacent panels.

In a preferred embodiment, the panels are fiber cement.

In a preferred embodiment, the adjacent panels are positioned with nogap between them. In another preferred embodiment, the adjacent panelsare positioned with a gap between them. Preferably, the gap is about ⅛″wide.

In a preferred embodiment, the backing material is a fabric. Preferably,the backing material is from about 0.0005″ to about 0.04″ thick. Thefabric is preferably a non-woven polyester fabric or a polyamide mesh.Preferably, the backing material is about 3″ wide.

In a preferred embodiment, the backing material is applied as a jointtape, wherein the joint tape comprises an adhesive preapplied to a faceof the backing material.

In a preferred embodiment, the caulkless elastomeric joint furthercomprises a ceramic putty applied over the backing material. In anotherpreferred embodiment, the caulkless elastomeric joint further comprisesan elastomeric joint filler applied over the ceramic putty.

In an preferred embodiment, an elastomeric finish is applied to thepanelized wall system. Preferably, the elastomeric finish comprises anelastomeric primer and an elastomeric texture layer, or is a texturecoating.

In a preferred embodiment, the frame is a wood frame. In a preferredembodiment, the frame comprises shear panels. In a preferred embodiment,the frame comprises a moisture barrier. In a preferred embodiment, theframe comprises a water break.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a photograph of a conventional fiber cement panel seam.

FIG. 2 is a photograph of an example of seam failure due to cracking ona conventional synthetic stucco application.

FIG. 3 is a photograph illustrating “peaking” at a fiber cement panelseam.

FIG. 4 is a top view of a trough-edge building panel.

FIG. 5 is a cross section of a trough-edge building panel.

FIG. 6 is a cross section of an alternative embodiment of a trough-edgebuilding panel.

FIG. 7 is a cross section of an elastomeric joint formed at the seam ofadjacent trough-edge panels.

FIG. 8 is a key for the dimensions in TABLE 1 for a trough-edge buildingpanel.

FIG. 9A and FIG. 9B are cross sections of a first embodiment of abuilding panel with an embossed edge and an elastomeric joint using thepanel.

FIG. 10A and FIG. 10B are cross sections of a second embodiment of abuilding panel with an embossed edge and an elastomeric joint using thepanel.

FIG. 11A and FIG. 11B are cross sections of a third embodiment of abuilding panel with an embossed edge and an elastomeric joint using thepanel.

FIG. 12A and FIG. 12B are cross sections of a fourth embodiment of abuilding panel with an embossed edge and an elastomeric joint using thepanel.

FIG. 13 is a cross section of a first embodiment of an elastomeric jointmade according to METHOD 1–METHOD 10.

FIG. 14 is a cross section of a second embodiment of an elastomericjoint made according to METHOD 1–METHOD 10.

FIG. 15 is a flowchart illustrating METHOD 1 for making an elastomericjoint.

FIG. 16 is a flowchart illustrating METHOD 2 for making an elastomericjoint.

FIG. 17 is a flowchart illustrating METHOD 3 for making an elastomericjoint.

FIG. 18 is a flowchart illustrating METHOD 4 for making an elastomericjoint.

FIG. 19 is a flowchart illustrating METHOD 5 for making an elastomericjoint.

FIG. 20 is a flowchart illustrating METHOD 6 for making an elastomericjoint.

FIG. 21 is a flowchart illustrating METHOD 7 for making an elastomericjoint.

FIG. 22 is a flowchart illustrating METHOD 8 for making an elastomericjoint.

FIG. 23 is a flowchart illustrating METHOD 9 for making an elastomericjoint.

FIG. 24 is a flowchart illustrating METHOD 10 for making an elastomericjoint.

FIG. 25 is a cross section of an elastomeric joint made according toMETHOD 11.

FIG. 26 is a flowchart illustrating METHOD 11 for making an elastomericjoint.

FIG. 27 is an elevation of a panelized wall system with elastomericjoints.

FIG. 28 is a flowchart illustrating a method of fabricating a panelizedwall system with elastomeric joints.

FIG. 29 illustrates the comparative performances of a wall constructedaccording to U.S. Pat. No. 5,732,520 and a wall constructed according tothe present disclosure in a racking test.

FIG. 30 is a cross section of a joint tape.

FIG. 31A and FIG. 31B are top and cross-sectional views of anadhesive-edge panel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Disclosed herein is a system for constructing, from substrate panels,walls with synthetic stucco finishes that resist cracking. Embodimentsof the disclosed wall system are constructed from combinations of thecomponents defined below.

Definitions

Joint. The term “joint” as used herein refers both to a structure formedby the edges or corners of adjacent building panels, and a system ofcomponents used to fill or cover this structure. The intended meaningwill be clear by context. The term “seam” is used interchangeably withthe first sense of “joint,” but not the second. A “joint” in the firstsense or “seam is formed by two adjacent panels that have no gap betweenthem, i.e., butted together, or with a gap between them.

Building Panels. The building panels of the present application are madefrom substrates suitable for interior or exterior construction. Thepanels may be flat or embossed, and may also have textured surfaces. Thesubstrate may be inorganic, organic, or a combination thereof. Fiberreinforced inorganic substrates are preferred, for example glass matreinforced cement boards, glass mat reinforced gypsum boards, andmaterials such as Georgia Pacific's Dens-glass Gold and United StatesGypsum's Aquatough. It will be appreciated, however, that the method maybe applicable to other fiber reinforced inorganic substrates as well asother substrates, including but not limited to aluminum, other cementcomposites such as scrimboard, wood, plywood, oriented strand board(OSB), wood composites, gypsum boards such as described in U.S. Pat. No.5,718,759, the entirety of which is incorporated by reference, andplastics such as polymer foam composite panels such as expandedpolystyrene foam.

A particularly preferred substrate is fiber cement (FC). Fiber cementpanels can be fabricated by conventional methods, for example, theHatschek process. Fiber cement panels can be either pretreated oruntreated with a coating to modify water absorption through the panelface. Fiber cement panels can also be treated with a sealer, primer, orother coating.

While the components of the disclosed embodiments of the invention areselected to best work with fiber cement panels, it will be appreciatedthat similar components can be selected to achieve the same performancewhen used with building panels composed of other substrates.

Caulk. In those embodiments using caulk, the caulk is preferably a highsolids, non-shrinking, permanently flexible caulk made from 100%polymer, such as a moisture cure polyurethane, moisture curesilicone-based adhesive, and silane-based adhesive. More preferably, thecaulk is a 100%-solid moisture-cure polyurethane that has good adhesionto the cementitious boards, to the adhesive applied to the backingmaterial, and to the backing material. An example of a suitable 100%polyurethane caulk such is Chem-calk 900 (Bostik Findley).

Adhesives. As described hereinafter, an adhesive layer is disposedbetween the building panel and a backing material. Elastomeric adhesiveshaving long elongation are preferred adhesives. Preferably, theelongation is greater than about 20%. An adhesive layer preferably has acertain thickness that allows it to slip and distribute the movement ofthe panels to the entire backing material, preventing cracking of thefinish coat. Thicker and softer adhesive layers generally slip moreeasily, although the minimum thickness required to provide the desiredslip characteristics will vary for each different adhesive. A preferredadhesive layer thickness is from about 0.001″ to about 0.04″. A thinneradhesive layer is easier for the finish to hide, however, and may bepreferred to provide a superior finish. The adhesive layer may include asingle adhesive or several adhesives, for example, a dual adhesivesystem.

The elastomeric joints disclosed herein use an adhesive that iselastomeric, distributing the movement of the panels to the entirebacking material. In certain embodiments, the adhesive also anchors theedges of the backing material to the building panel, preventing theedges from slipping. The adhesive may be a pressure-sensitive ornon-pressure-sensitive adhesive. The former class of adhesives isparticularly preferred. These adhesives are normally tacky at roomtemperature and adhere to a surface by application of light fingerpressure. In another embodiment, a hot-melt adhesive is preferred.

The adhesive may include water-based, solvent-based, and 100%solid-based adhesives. Preferred adhesives include one-component andtwo-component adhesives. The adhesive may be based on, for example,general compositions of polyacrylate, polyvinyl ether, rubber (e.g.,natural rubber), isoprene, polychloroprene, butyl rubber, neoprenerubber, ethylene propylene diene rubber (EPDM), polyisobutylene,butadiene-acrylonitrile polymer, thermoplastic elastomers,styrene-butadiene polymer, poly-alpha-olefin, amorphous polyolefin,silicone, ethylene-containing copolymer (e.g., ethylene vinyl acetate,ethylene ethyl acrylate, ethylene n-butyl acrylate, and ethylene methylacrylate), polyurethane, polyamide, epoxy, polyvinylpyrrolidone andpolyvinylpyrrolidone copolymers, polyesters, and mixtures or copolymersthereof. The adhesive layer may also contain additives or modifiers, forexample, tackifiers, plasticizers, fillers, antioxidants, stabilizers,pigments, curatives, crosslinkers, solvents, etc.

Certain embodiments of the present invention further comprise a secondadhesive. The second adhesive is relatively more rigid than the firstadhesive. The rigid second adhesive, applied at the edges of the backingmaterial, anchors the edges of backing material to the panels,preventing cracking of the finish at the edges of the backing material.

The second adhesive may be selected from the same class of adhesives asthe first adhesive, i.e., pressure-sensitive or non-pressure-sensitiveadhesives; hot-melt adhesives; water-based, solvent-based, and 100%solid-based adhesives; and one-component and two-component adhesives.Preferred second adhesives include, but are not limited to, water-basedand solvent-based acrylic adhesives, modified acrylic adhesives,formaldehyde-based adhesives, moisture-cure polyurethanes, two-partpolyurethanes, two-parts epoxies, one-part and two-part silicone-basedadhesives, natural adhesives such as starch and protein, inorganicadhesives, polymer-latex adhesives, and mixtures thereof. In anotherpreferred embodiment, the finish coat is the second adhesive. In thisembodiment, the backing material is permeable to the finish coat,allowing the finish to adhere directly to the panel substrate beneaththe backing material.

The first and second adhesives may be applied by solvent coating;extrusion, either separately from or simultaneously with the backingmaterial; hot melt coating; calendaring; curtain coating; gravure orpattern coating; spray coating; lamination; pressure feed die coating;knife coating; roller coating; or any other suitable technique. It isexpressly contemplated that the adhesive layers can be eithercontinuous, such as a uniform layer, or discontinuous, such as strips orbands, dots, or another patterned or random arrangement of discreteadhesive portions. The thickness of adhesive is controlled according tothe requirements of the application.

Preferred first and second adhesives include styrene-isoprene-styreneblock-copolymer adhesives, for example PL919 pressure sensitive adhesive(SIA Adhesives); styrene-butadiene, polymer adhesives, for example H400pressure sensitive adhesive (Heartland Adhesives & Coatings); and butylrubber adhesives, for example PVT-3300 (Carlisle Coating &Waterproofing) and HL 2203 (H.B. Fuller). Another preferred secondadhesive is a polyurethane adhesive, for example UR-0210 moisture-curedpolyurethane (H.B. Fuller).

Backing Material. The backing material is a fabric or film to which theadhesive components of the disclosed panelized wall systems adhere,i.e., the adhesives, caulk, joint filler, ceramic putty, and finishcoating, particularly cement-based stucco coatings and latex-basedtexture coatings. Preferably, the backing material stretches and moveswith the building panels without tearing the backing material andwithout cracking the finish coating covering the backing material.Preferred backing materials include, but are not limited to, cellulosepapers, plastic films, metal foils, and woven or non-woven fabrics.

Of these materials, fabric is preferred. Preferred fabrics arepolyester, polypropylene, polyethylene, polyamide, cellulose, cotton,rayon, glass fiber, or combination of two or more of these materials.Preferably, the backing material has a selected moisture absorptioncharacteristic that provides a monolithic appearance to the finish coat.The fabric should adhere well to the joint filler compounds and texturecoatings of the disclosed panelized wall system. A preferred backingmaterial is made from a non-woven polyester fabric, for example Sontara(Dupont). Sontara 8801 is 16 mil (0.016″) thick, Sontara 8000 is 20 mil(0.020″) thick, and Sontara 8004 is 25 mil (0.025″) thick. Particularlypreferred are backing materials made from a non-woven polyester fabricthat is greater than about 16 mil thick. Another preferred backingmaterial is made from a polyamide (Nylon) mesh fabric.

Preferred backing materials are easily bonded by the adhesives usedherein, with good adhesion under dry, equilibrium, and water-soakedconditions, and at different temperatures. Preferably, the backingmaterial has an elongation of about 20% or more, more preferably fromabout 20% to about 500%, wherein the preferred range includeselongations of about 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%,70%, 75%, 80%, 85%, 90%, 95%, 100%, 110%, 120%, 130%, 140%, 150%, 160%,170%, 180%, 190%, 200%, 210%, 220%, 230%, 240%, 250%, 260%, 270%, 280%,290%, 300%, 320%, 340%, 360%, 380%, 400%, 420%, 440%, 460%, 480%, and500%.

A very thin fabric backing material may not be sufficiently strong tomaintain a solid joint. On the other hand, a thick fabric may bedifficult to hide beneath the finish. A preferred fabric thickness isfrom about 0.0005″ to about 0.04″, more preferably from about 0.001 ″ toabout 0.03″. A preferred width of backing material is from about ¼″ toabout 12″. A more preferred width of backing material is from about ½″to about 8″. A very narrow backing material may not sufficiently coverany gaps between the panels or effectively distribute the panelmovements. A very wide backing material is less cost effective.

Joint Fillers. Certain embodiments of the disclosed elastomeric jointinclude one or more joint fillers applied over the backing material,adhesive layers, any troughs, and embossed edges or other edge profilingon the building panels. The joint filler fills any depressions in thejoint or trough areas, providing a smooth surface for the texturecoating. The joint filler preferably has elastomeric propertiesspecifically selected to complement the expansion and contractioncharacteristics of the elastomeric tape applied beneath and finishcoatings applied above the joint filler. The joint filler is preferablya mixture that includes a polymer binder, one or more inorganic fillers,thickeners, pigments, and inorganic binders.

Polymer latex emulsions such as acrylic emulsions are well known in theart and are suitable as the elastomeric polymer binder. Other suitablepolymer binders include redispersable powdered acrylics, polyurethanes,and silicones.

Inorganic binders can be used in the joint filler material to providehardness and scratch resistance. One example of a suitable inorganicbinder is a combination of soda lime glass and acrylic acid, in whichthe soda lime glass reacts with the acrylic acid to form a gel. As thisgel dries, it hardens the joint filler material.

Calcium carbonate, kaolin clay, aluminosilicate, and other silicateminerals are examples of suitable inorganic fillers, as are well knownin the art. The inorganic filler may also be a low-density expandedmineral such as perlite. Hollow aluminosilicate or polymericmicrospheres are examples of inorganic fillers that both modify thedensity of the joint filler and control the expansion and contractioncharacteristics.

Suitable thickeners are well known in the art, and include celluloseethers, vegetable gums, clays, and synthetic polymers such as ammoniumsalts of acrylic polymers.

Pigments may be white, for example titanium dioxide, kaolin clay, orcalcium carbonate, or colored, for example iron oxides. Pigmentssuitable for coloring the joint filler are well known in the art.

The joint filler may be smoothed over the joint by any method known tothe art, for example by using a trowel and float. Typically, the jointfiller is applied in one or more thin layers in order to minimize thevisibility of the joint. As will become apparent below, the thickness ofthe joint filler application depends on a variety of factors includingthe thickness of the backing material, the thickness of the adhesive,the presence or absence of trough edges on the panels, and the presenceor absence of other edge features on the panels. Once applied, the jointfiller is typically allowed to cure (harden) for 1–4 hours, depending ontemperature and humidity conditions. After curing, the joint filler maybe smoothed by sanding. A preferred joint filler is a ceramic putty, forexample Fill-n-Build (Global Coatings), which contains by weight acryliccopolymer emulsion (30%), hydrated aluminum silicate mineral (19.5%),soda lime borosilicate glass (10%), kaolin clay (8%), titanium dioxide(4%), and ammonium salt of acrylic polymer (1%).

Certain disclosed embodiments use an elastomeric joint filler, whichprovides an elastomeric surface to the exterior face of the joint. Anelastomeric joint filler contains a higher proportion of polymer to makeit more elastomeric, and is typically smoothed over the surface of thejoint using a trowel and float and allowed to cure for about 1–4 hours,depending on temperature and humidity. A preferred elastomeric jointfiller is Acracream (Global Coatings), which contains by weight acrylicpolymer emulsion (55%), calcium carbonate (30%), polymeric microspheres(3.9%), and titanium dioxide (2%).

The elastomeric joint in certain embodiments of the present inventionincludes an elastomeric joint filler applied over a ceramic putty.Preferably, the elastomeric joint filler is selected to match theelastomeric properties of the synthetic stucco coating, furtherenhancing the crack resistance of the joint.

Finish. The finish is preferably an elastomeric finish and may beapplied by any means suited to the particular finish, for example,troweling, spraying, rolling, or brushing. The finish coating is alsoreferred to as “finish” and “surface coating.”

A preferred finish is a textured finish simulating stucco, selected forits water resistance and flexibility. This type of finish is referred toas “synthetic stucco” or simply “stucco.” Such finishes are well knownin the art and are generally contain a polymer binder, inorganic filler,water, and pigments. Texture coatings are generally applied with a spraygun in one or more coats, for example, a primer and a texture layer,which are allowed to dry between coats. Commercially available syntheticstucco finishes compatible with the disclosed panelized wall systemsinclude Multitex (Multicoat, Costa Mesa, Calif.), Akro-Gold (OmegaProducts), and Harditexture (James Hardie, Fontana, Calif.).

Suitable finish coats may also be applied by other means. For example,Colorseal Plus (Global Coatings) is applied to the entire wall using apaint roller and allowed to dry for 1 to 2 hours, providing a surface ofuniform moisture absorption properties and uniform color. Thecomposition of Colorseal Plus is typical and contains by weight aqueousacrylic emulsion (39%), calcium carbonate (35%), water (19%), titaniumdioxide (5%).

A final coating of Carrara texture-coat is then shot onto the wall witha hopper gun. The surface may be left “as is” for a rough finish, orhand-troweled to the desired smoothness. The finish is protected untilcured, typically 8–24 hours.

Frame. As used herein, a frame is any frame capable of supporting thedisclosed panelized wall system. Preferred frames are wood or metalframes. Preferably, the vertical members of the frame are spaced about16″ apart, up to about 24″ apart or more, and optionally wrapped in amoisture barrier.

Another preferred frame is a shear wall, a frame to which shear panels,typically plywood or oriented strandboard (OSB) panels, are attached forreinforcement. Other examples of a suitable frame include a tilt-upwall, or a previously finished wall, such as wall finished with acladding.

Preferably, the building panels are positioned on the frame with theedges of adjacent panels sharing a common framing member, for example, astud. In some embodiments, the panels are positioned with a gap ofpredetermined width between adjacent panels, the gap falling directlyover a framing member. In another embodiment, the panels are installedwithout gaps, i.e., butted edge-to-edge. In embodiments with gapsbetween adjacent panels, the width of the gap is preferably from about1/16″ to about ⅛″, allowing for building and panel movement, andshrinkage and expansion of the building panels. The bottom edges of thewall panels are preferably positioned on the wall level to ensure thatthe panels are level and plumb.

The building panels may be attached to the frame by any means known inthe art. Mechanical means include nails, screws, staples, nuts andbolts, clips, and the like. The panels may also be fastened to the framewith chemical means, for example, with an adhesive or a tape. Apredetermined pattern of fasteners is typically used to fasten thebuilding panels to the frame. Preferred fasteners are screws and nails.

Moisture Barriers. Moisture barriers are used in certain embodiments ofthe disclosed panelized wall systems. Any type of moisture barrier, alsocalled water barriers and weather-resistive barriers, known in the artmay be used, for example asphalt paper, polyethylene-based sheeting,reinforced plastic sheeting, or foam insulation panels. A preferredmoisture barrier is asphalt paper, also called asphalt-impregnatedpaper. The moisture barrier is installed between the frame and thebuilding panels.

Water Management Systems. Certain embodiments of the disclosed panelizedwall systems comprise water management systems, for example, waterbreaks, rain screens, or weep screens. Preferred water managementsystems are designed for use under panelized substrates, for exampleHomeslicker Rain Screen (Benjamin Obdyke, Horsham, Pa.). The watermanagement system is typically installed beneath the building panels

Release Liner. A release liner or release paper is a paper or plasticfilm coated with a release agent. The release liner is laminated to anadhesive layer, protecting the adhesive layer. A preferred release agentis a silicone-based polymer. The thickness of release liner ispreferably from about 0.0002″ to about 0.005″. The release liner is easyto be peeled from the adhesive layer in order to expose the adhesive.

Testing. Tensile testing was performed on sample elastomeric joints madefrom 2″×5″ 5/16″ specimens of primed fiber-cement panel (Hardipanel,James Hardie, Fontana, Calif.) The sample joints were fabricated on the2″ sides of two panel specimens. In test samples with caulked joints,the caulk was a 100% polyurethane caulk (Chem-calk 900, Bostik Findley).The caulk was applied to a ⅛″ gap between the panels, the caulk surfacesmoothed, and the caulk allowed to cure overnight. The test samples werefinished with a medium texture ( 1/16″) elastomeric latex stucco(MultiTex, Multicoat, Costa Mesa, Calif.). The thickness of the texturecoating varied with the texture pattern, from about 0″ to about 1/16″.

Tensile testing was performed on a universal test machine (Instron). Inthe tensile tests, a sample test joint was mounted in the testingmachine and stretched, typically at 6 mm/min, until the finish coatingcracked. The strain of the joint at failure was calculated from thesample geometry and machine crosshead displacement.

Elastomeric Joints

FIG. 1 is a photograph of a conventional fiber cement panel joint 100.Panel joint 100 comprises two adjacent fiber cement substrate panels 110separated by a ⅛″ gap at the seam 120 and covered by tape 130.

FIG. 2 is a photograph of a conventional synthetic stucco application200. The stucco finish typically has a number of valleys 210. Valleys210 are particularly susceptible to joint read, where cracks like crack230 form near the joint 220. The cracks are caused by the movementbetween the fiber cement panels and the tape that joins two panelstogether beneath the stucco.

FIG. 3 is a photograph of a synthetic stucco application where packinghas occurred. Peaking is caused by movement of the fiber cement panels,more particularly, environmentally induced expansion and shrinkage. Thismovement causes failure of the adhesive bond between the substrate andthe joint tape and caulk, causing the stucco over the joint to floathigher or lower than the stucco over the field of the panels.

One embodiment of the present invention provides a building panel with athough adjacent to an edge of the panel. These trough-edge panels inconjunction with a joint tape create an elastomeric joint that isresistant to cracking at or near the joint and minimizes joint readcaused by the height differential between the panel and the edge of thejoint tape that covers the seam between adjacent panels. The panel isdesigned such that the edge of the joint tape lies in the trough,concealing the edges below the surface plane of the panel, such that thefinish coat provides a uniform, flat finish.

FIG. 4 and FIG. 5 are top and cross sectional views, respectively, of afiber cement panel 410 with a trough 420 according to one embodiment ofthe present invention, which overcomes the joint read and crackingproblems illustrated in FIG. 2 and FIG. 3. The trough 420 is spacedinwardly from the edge 450 of the panel. In one embodiment, the side ofthe trough 420 closer to the edge 450 of the panel forms a wall 430, thewall meeting a floor 440 lower than the surface 460 of the panel betweenthe trough 420 and the edge 450 of the panel. The embodiment illustratedin FIG. 5 also has a second wall 470 opposite to the first wall 430 thatalso meets the floor 440, forming a substantially rectangular trough420. The edge of the joint tape preferably lies on the floor 440 of thetrough 420. In a preferred embodiment, the trough 420 is spaced inwardlyfrom the edge 450 of the panel by a distance χ of about 1 ″. In thisembodiment, the trough 420 has a rectangular cross section with a widthα of about 0.63″ and a depth β of about 0.034″. In another preferredembodiment, the trough 420 extends to the edge of the panel such thattrough 420 does not include a wall 430. FIG. 6 illustrates yet anotherembodiment in which the surface 460 between the trough 420 and the edge450 of the panel slopes downwards towards the edge 450. The slopedsurface reduces peaking in elastomeric joints that use caulk between thepanels.

Fiber cement panel 410 may be fabricated by any method known in the art,for example, by the Hatschek process. The trough 420 may be formed byembossing, using a plate press, using a profiled accumulator roll in theHatschek process, or by post-cure machining, as described below. Theedges of the tape fall below the surface of the fiber cement panels 410,preventing joint read. The trough 420 illustrated in FIG. 5 and FIG. 6has a rectangular cross section; however, it will be appreciated thatthe trough may assume other shapes, as described below.

FIG. 7 illustrates a joint incorporating a trough-edge panel. Thissystem includes two adjacent panels 710 separated by a gap. In theillustrated embodiment, caulk 720 is applied to the gap. It will beappreciated that the gap and/or caulk are optional. For example,adjacent panels may be separated by a gap that is not caulked. Apreferred embodiment described below, has neither a gap nor any caulkbetween adjacent panels. Tape 750 is applied over the edges of thepanels 710, with the edges 755 of the tape falling inside the troughs760 of the panels 710. Synthetic stucco 780 is applied over the panels710 to cover the tape 750.

FIG. 8 is keyed to the dimensions of a preferred panel substrateprovided in TABLE 1 below.

TABLE 1 Feature Reference Preferred Range Preferred Board Thickness Aabout 3/16″–2″ about 5/16″ Trough Edge Offset B about ½″–3″ about 1½″Trough Width C about ⅛″–2″ about ¾″ Trough Depth D about 0.005″–0.25″about 0.050″ Trough Relief Angle ∠E   about 5°–90° about 45° or roundedSurface Offset Depth F about 0–0.1″ about 0.010″ Edge Taper Width Gabout 0–0.25″ about 0.060″ Edge Taper Depth H about 0–0.25″ about 0.060″Edge Taper Angle ∠I   about 0–90° about 15° Edge Thickness J about3/16″–2″ about 5/16″

TABLE 1 provides preferred dimensions for fiber cement building panels.The board thickness A is selected for the particular buildingapplication. Thicker panels are stronger, but are heavier and moredifficult to handle, more expensive, and require more warehousing space.The trough edge offset B and trough width C are selected such that theedges of the selected joint tape fall within the troughs of adjacentpanels. Widening the trough width C allows for a greater range of jointtape widths to be used with a particular panel, as well as flexibilityin providing a gap or no gap between adjacent panels. Without beingbound by any theory, our current belief is that the motion of the panelsis accommodated by that part of the tape outside the troughs, however.Accordingly, a narrower trough width C would provide a more flexiblejoint. Moreover, a narrow trough requires less joint filler or surfacefinish to fill, facilitating hiding the joint. The preferred dimensionsfor the trough edge offset and trough width contemplate a 3″-wide jointtape and either no gap or a gap no wider than about ⅛″ between adjacentpanels. The trough depth D is selected such that the top of the jointtape within the trough is approximately level with the board thicknessA. Consequently, the preferred trough depth approximates the thicknessof the joint tape. A trough relief angle E less than 90° makes hidingthe joint easier. A shallower angle or rounded edge minimizes thevisibility of the trough wall. The surface offset depth F reduces thepanel thickness A to the edge thickness J, further reducing the changesin elevation in the taped joint, and again, reducing the visibility ofthe joint. The edge panel width G, depth H, and angle I are selected toreduce peaking in caulked joints. It will be appreciated that thefeatures and dimensions illustrated in TABLE 1 are merely exemplifying,and thus, the panel can have other features and dimensions. For example,the very edge of the board can be cut with multiple angles, which mayassist in eliminating peaking and/or the need for caulk.

EXAMPLE 1 Comparative Testing of Joint Flexibility for Trough-EdgePanels

Tensile testing of the flexibilities of joints constructed from panelswith different embossed trough depths was performed on a universaltesting machine at a strain rate of about 5 to 10 mm per minute. Threedifferent joint configurations were tested on a substrate of 5/16″-thickfiber-cement panel (Hardipanel, James Hardie, Fontana, Calif.). Eachjoint was caulked, taped with 3″-wide tape, and finished with asynthetic stucco finish. The joints were caulked with a 100% urethanecaulk (Chem-calk, Bostik Findley), taped with a 3″-wide elastomeric tape(Multicoat Elastomeric Joint Tape, Multicoat, Costa Mesa, Calif.)centered over the joint, and finished with a medium grit worm finishsynthetic stucco (MultiTex, Multicoat, Costa Mesa, Calif.). In thepanels with troughs, the troughs were spaced such that the edges of thetape fell within the troughs.

The testing results reported in TABLE 2 demonstrate the improved jointflexibility provided by joints made with trough-edge panels compared tothose made with flat panels. The trough depths were selected to providejoint flexibility while maintaining an aesthetically acceptableappearance. In test A, the control, the panels were smooth with no edgetrough. In test F, each panel was embossed with a single shallow battenwith a rectangular cross section approximately 0.077″ deep running thelength of the panel. In test E, each panel was embossed with a singledeep batten with a rectangular cross section approximately 0.086″ deeprunning the length of the panel. In both trough-edge panels, the troughsedge offset (B) was 1½″ and the trough width (C) was ¾″.

As shown in TABLE 2, the panel with the shallow trough (test F) providedthe most flexible joint system, stretching 10.48 mm (13.8%) beforefailing. In each case, the joint failed when the edge of the tapeslipped from the panel surface at the top and bottom of the tape. In nocase did the joint fail at the seam between the panels.

TABLE 2 Test Trough Depth Tensile Joint Stretch to Failure A No Trough 4.58 mm (6.0%) F 0.077″ 10.48 mm (13.8%) E 0.086″  9.01 mm (11.8%)

The results provided in TABLE 2 demonstrate that the joint flexibilityas determined by joint stretch, more than doubled in the trough-edgejoint F compared to the smooth, flat panel joint A. This greaterflexibility translates into increased resistance to joint cracking. Theadded stucco finish used to conceal the trough also conceals the edgesof the tape, reducing joint read. The trough-edge joint alsodemonstrated improved shear strength of the DEFS coating.

Irrespective of the thinness of a joint tape or backing material, whenused on a flat panel, there will be a height difference between the topof the joint tape or backing material and the surface of the panel. FIG.9–FIG. 12 illustrate panels with embossed edges designed to provide animproved finish. Preferably, the depth “a” of the embossed edge is thesame as the thickness of the backing material and adhesives. Preferably,twice the width “b” of the embossed edge plus the width of any gapbetween adjacent panels equals the width of the backing material. Thetop surface of the backing material and the front surface of the panelsare preferably coplanar, resulting in a monolithic appearance even whenusing a thin finish coat.

The embossed edge may be flat as in FIG. 9. It may be sloped as in FIG.10 and FIG. 11, or have steps as in FIG. 12, or have curved profile (notshown), or any combination thereof. The transition between the side-walland bottom of the embossed edge may be a sharp angle as in FIG. 9–FIG.12 or curved (not shown). Panels with embossed edges may also compriseedge troughs as described above. The disclosed methods of fabricatingelastomeric joints are applicable to flat panels, panels with embossededges, trough-edge panels, and trough-edge panels with embossed edges.

For fiber cement panels, the embossed edges are preferably produced byembossing, although they may also be produced by other methods, forexample by using a plate press, using a profiled accumulator roll in theHatschek process, or by post-cure machining.

FIG. 13 and FIG. 14 are cross-sectional views of elastomeric joints 900that include two adjacent panels 910; optionally, a caulk 920; a firstadhesive 930; a second adhesive 940; a backing material 950. Certainembodiments of the elastomeric joint may also have a joint filler, as isdiscussed in greater detail below. The panels may be flat, as shown inFIG. 13; have trough edges 960, as shown in FIG. 14; have embossed edges(not shown); or a combination thereof. The surface is covered with anelastomeric finish 980, preferably, a texture coating or syntheticstucco finish. Adhesive 930 is at the center of the joint and adhesive940 is at the edges of the joint. The adhesives and backing materialdistribute the panel movement from the seam formed by the panels to theentire backing material greatly reducing strain on the finish coating,which prevents cracking of the finish.

The caulk 920 fills the gap between adjacent panels 910. It provides asurface for the elastomeric adhesive or adhesives applied thereover,supporting the adhesives, backing material, and texture coating undertensile and compressive forces across the joint. A joint without caulkmay show peaking at the joint or cracking in the coating.

The adhesive layer may include a single adhesive or dual adhesives. FIG.13 and FIG. 14 illustrate a dual adhesive system. In a single adhesivesystem, adhesives 930 and 940 are the same adhesive. In a dual adhesivesystem two different adhesives are used. As shown in FIG. 13 and FIG.14, a first adhesive 930 used in the central part of the joint isrelatively more flexible than a second adhesive 940 used at the edges ofthe joint. The more flexible first adhesive 930 distributes the panelmovements across the entire backing material 950, while the more rigidsecond adhesive 940 anchors the edges of the backing material,preventing cracks that arise from tape slippage.

EXAMPLE 2 and EXAMPLE 3 below illustrate the advantages of using both anadhesive layer and a backing material in an elastomeric joint. InEXAMPLE 2, the joint is fabricated without an adhesive layer. In EXAMPLE3, the joint has no backing material. Neither joint successfullywithstood significant panel movement.

EXAMPLE 2 Joint Without an Adhesive Layer

Two 2″×5″ primed fiber cement specimens (James Hardie, Fontana, Calif.)were arranged with a ⅛″ gap between them. The gap was filled with 100%polyurethane caulk (Chem-calk 900, Bostik Findley), the caulk surfacesmoothed, and the caulk allowed to cure overnight. A 2″×3″ piece ofbacking material (Sontara 8801 fabric, Dupont) was centered and appliedover the joint, and the surface finished with a medium texture ( 1/16″)elastomeric latex stucco (Multicoat, Costa Mesa, Calif.). The thicknessof the texture coating was from about 0″ to about 1/16″, varying withthe texture pattern on the surface. No additional adhesive layer wasapplied between the cementitious board and the fabric. Instead, thetexture coating penetrated the backing material reaching the fibercement panel beneath, and adhering the backing material to the panels.

The sample was equilibrated at 72° F. at 50% relative humidity for 7days before tensile testing. The texture coating cracked when the jointwas stretched about 1.6 mm (2.1%) at about 6 mm/min at 72° F. Thus, thistype of joint would not withstand the normal expected movement of 4′×8′fiber cement panels, which may shrink 3–5 mm or more (3.9–6.6% for a3″-wide tape).

Other fabrics, such as other Sontara Series 8000 polyester fabrics(Dupont) and nylon fabrics were also tested in this type of joint. Nonewithstood more than 3 mm (3.9%) of stretching before cracking thelatex-based texture coating.

EXAMPLE 3 Joint without a Backing Material

Two 2″×5″ primed fiber cement specimens (James Hardie, Fontana, Calif.)were arranged with a ⅛″ gap between them. The gap was caulked and curedas described in EXAMPLE 2. A 2″×3″ layer of 0.028″ thick PVT-3300adhesive (Carlisle Coating & Waterproofing Inc.) was centered andapplied over the joint. The test sample was finished and the finishcured as in EXAMPLE 2. Tensile testing indicated that the texturecoating cracked when the joint was stretched about 1–2.5 mm (1.3%–3.3%)at 6 mm/min at 72° F. Thus, this type of joint would not withstand thenormal expected movement of 4′×8′ fiber cement panels. Furthermore,because the adhesive layer did not absorb the latex-based texturecoating, the joint was clearly visible after the coating cured.

EXAMPLE 4 Comparative Test of Backing Materials

A comparative test of backing materials was performed. The backingmaterials were three non-woven polyester fabrics (Sontara 8000, Sontara8004, Sontara 8801, Dupont). For each test, a joint tape was preparedfrom a 2″×3″ piece of the test backing material and a 0.006″ layer of astyrene-isoprene-styrene block copolymer adhesive (PL 919, SIAAdhesives). For each test, the edges of two 2″×5″ specimens of primedfiber cement panels were butted with no gap between them. The joint tapewas centered on the joint and applied. The test sample was finished andthe finish cured as described in EXAMPLE 2.

The test samples were equilibrated for 7 days at 72° F. at 50% relativehumidity. Tensile testing was performed at 6 mm/min at 72° F., and thestrain (stretching) at which the finish cracked was recorded. Theproperties of the backing materials and test results are provided inTABLE 3.

TABLE 3 Elongation Backing Machine Material Direction Cross DirectionStretch Before Cracking Sontara 8000 38% 114% 10–12 mm (13.1–15.7%)Sontara 8004 33% 110% 9–11 mm (11.8–14.4%) Sontara 8801 18%  78% 4–7 mm(5.2–9.2%)

This example shows importance of the elongation of the backing materialto the performance of the joint. Because a joint movement of 3–5 mm istypical for 4′×8′ panels, the 18% elongation of the Sontara 8801 fabricappears to produce an insufficiently flexible joint using a 3″-widetape. Accordingly, we prefer a backing material with an elongation ofabout 20% or more.

The methods described below are the preferred methods of joiningbuilding panels with elastomeric joints. These methods preferablycomprise some or all of following steps: applying caulk between adjacentbuilding panels; applying adhesive on a backing material or on the edgesof construction panels such as fiber cement panels; applying a releaseliner on the adhesive applied to the backing material or the edges ofthe panels; removing the release liner and applying an adhesive-coatedbacking material to adjacent fiber cement panels or applying a backingmaterial to adjacent adhesive-coated fiber cement panels.

In practicing these methods, either a single adhesive or dual adhesivesmay be used as the adhesives 930 and 940 of FIG. 13 and FIG. 14. In asingle adhesive system, adhesives 930 and 940 are the same adhesive. Ina dual adhesives system, adhesives 930 and 940 are different adhesives.Preferably, the adhesive 930 is at the central portion of the joint andadhesive 940 is symmetrically disposed at the edges of the backingmaterial. Adhesive 930 may contact adhesive 940, and in fact, mayoverlap adhesive 940. In another embodiment, adhesive 930 and adhesive940 do not contact. The thicknesses of the layers of adhesives 930 and940 may be the same or different.

Eleven methods of fabricating an elastomeric joint are described below.The preferred backing material may be the same or different for eachmethod, and the preferred adhesive(s) may be the same or different ineach method. The building panels for each method may have plain edges,trough edges, embossed edges, or a combination thereof. TABLE 4 belowprovides a brief summary of the first ten methods.

TABLE 4 Adhesive 930 Adhesive 940 When When Method Location Applied ^(a)Location Applied ^(a) Single Adhesive Systems 1 Backing material BeforeN/A N/A 2 Edge of panel Before N/A N/A 3 Backing material or After N/AN/A edge of panel Dual Adhesive Systems 4 Backing material BeforeBacking material Before 5 Backing material Before Backing material Afteror edge of panel Backing material or After Backing material Before edgeof panel 6 Backing material Before Finish coat is After or edge of paneladhesive 140 7 Edge of panel Before Edge of panel Before 8 Edge of panelBefore Backing material After or edge of panel Backing material or AfterEdge of panel Before edge of panel 9 Backing material or After Backingmaterial After edge of panel or edge of panel 10 Backing material BeforeEdge of panel Before Edge of panel Before Backing material Before ^(a)“Before” means that the adhesive is installed prior to the installationof the building panels to the frame. “After” means that the adhesive isapplied after the installation of the building panels to the frame.

An elastomeric joint for fiber cement panels may be made from a singleadhesive plus a backing material. The adhesive is preferably anelastomeric material that slips with the movement of the building panelsat the center of the joint, but does not slip at the edges of thebacking material. The expected movements of 4′×8′ fiber cement panelswill not crack a flexible texture coating used with this joint system.

Method 1

FIG. 30 illustrates a preferred embodiment of a joint tape 3000 madefrom a backing material 950, a first adhesive 930, a second adhesive940, and an optional release liner 990. In METHOD 1 first adhesive 930and the second adhesive 940 are the same adhesive. FIG. 15 illustratesMETHOD 1 for fabricating an elastomeric joint in which the joint tape3000 is manufactured in steps 1510 and 1520. The joint tape can bepre-made, for example, by a tape manufacturer.

In step 1510, an adhesive layer 930 is applied to a face of a backingmaterial 950. A preferred adhesive is a pressure-sensitive adhesive,which may include a water-based, solvent-based, or 100% solid-basedadhesive. More preferably, the adhesive is a 100%-solid, hot-meltadhesive that does not depend on water or solvent evaporation forcuring. In step 1520, a paper or plastic film 990 coated with a releaseagent is optionally laminated to the adhesive layer of the joint tape. Apreferred release agent is a silicone-based polymer. The thickness ofrelease liner is preferably from about 0.0002″ to about 0.005″. Therelease liner is easy to be peeled from the adhesive layer in theapplication of the joint tape.

In step 1530, adjacent fiber cement panels 910 are installed asdescribed above. Panels are preferably installed with a ⅛″ gap betweenthe panels to allow for building and panel movement. In anotherpreferred embodiment, the panels 910 are butted together, leaving nogap.

In step 1540, caulk 920 is optionally applied between panels 910. Thecaulk is preferably applied flush with the surface of the panels 910.The caulk 920, preferably a high solids, non-shrinking, and permanentlyflexible caulk made from 100% solid urethane, provides a surface towhich the joint tape adheres and provides an even surface, supportingthe tape and stucco under tensile and compressive forces across thejoint.

In step 1550, the release liner is removed from the elastomeric jointtape and the exposed adhesive face of the joint tape is applied over thejoint between the panels 910. The joint tape is preferably centered overthe joint. The nominal 3″ elastomeric joint tape and flexible stuccofinish are capable of withstanding significant joint movement withoutcracking the stucco finish.

Each the following examples uses a 3″-wide backing material or tape toallow direct comparison of the results. Other widths of backing materialor tape may also be used.

EXAMPLE 5 Commercial Joint Tape

A commercially available elastomeric tape used in cementitious panelconstruction (Multicoat, Costa Mesa) is made from a fabric backing and apressure-sensitive adhesive. The adhesive on this tape is about 0.01″thick. Two 2″×5″ pre-coated fiber cement board specimens were arrangedwith a ⅛″ gap between them. The gap was caulked with a 100% polyurethanecaulk (Chem-calk 900, Bostik Findley), the caulk surface smoothed, andthe caulk allowed to cure overnight. A 2″×3″ piece of Multicoatelastomeric tape was centered and applied over the caulked joint. Thetest sample was finished with a medium texture coating (Multicoat, CostaMesa, Calif.). The thickness of the texture coating was about 0 to1/16″, varying with the texture pattern on the surface.

The sample was equilibrated for 7 days at 72° F. at 50% relativehumidity. The texture coating cracked when the joint was stretched about3.5 to 4 mm (4.6–5.2%) at 6 mm/min at 72° F. At 120° F., the texturecoating cracked when the joint was stretched 2 mm (2.6%). The crackingoccurred at the edges of the tape because of slipping of the tape edgeson the panels.

The joint was also tested statically. In a static test, the sample israpidly stretched to a predetermined length (over a few seconds). Thesample is held in the stretched state and the time required for thefinish to crack measured. After stretching the joint about 2.5 mm (3.3%)at 72° F., the texture coating cracked after 2 minutes. Thus, jointsmade from the commercially available 3″-wide joint tape may not bestrong enough to withstand the possible movement of 4′×8′ cementitiouspanels.

The 180° peel strength of the Multicoat tape was 10.3 lb/inch at 72° F.At 120°F., the 180° peel strength was only about 1 lb/inch. Underwater-saturation conditions, the 180° peel strength 4 lb/inch at 72° F.In each test, the test speed was 60 mm/min.

EXAMPLE 6

A joint tape was made with a 0.006″-thick layer of PL919pressure-sensitive adhesive (SIA Adhesives) on 3″-wide piece of Sontara8000 fabric (Dupont). Two 2″×5″ primed cementitious fiber cementspecimens were prepared and caulked as described in EXAMPLE 5. A 2″×3″piece of the joint tape was centered and applied to the joint. The tapewas centered over the caulk joint. The test sample was finished and thefinish cured as described EXAMPLE 5.

Under tensile testing at 6 mm/min, the texture coating did not crackuntil the joint was stretched about 10–12 mm (13.1–15.7%) at 72° F. The3″-wide elastomeric joint tape prepared in this example is capable ofwithstanding greater than the expected normal movement of 4′×8′ fibercement panels.

The 180° peel strength of this tape was about 10.6 lb/inch at 72° F. At120° F., the 180° peel strength was reduced to about 6.4 lb/inch. Underwater saturation conditions, the 180° peel strength was about 7 lb/inchat 72° F. This joint tape had better heat and water resistance than theMulticoat tape used in EXAMPLE 5.

EXAMPLE 7

A joint tape was made with a 0.006″-thick layer of H400 pressuresensitive adhesive (Heartland Adhesives & Coatings) on 3″-wide piece ofSontara 8000 fabric (Dupont). Two 2″×5″ pieces of primed fiber cementpanel (James Hardie, Fontana, Calif.) were butted together, leaving nogap. A 2″×3″ piece of the joint tape was centered and applied to thejoint. The test sample was finished and the finish cured as described inEXAMPLE 5.

Under tensile testing at 6 mm/min, the texture coating did not crackuntil the joint was stretched about 7 mm (9.2%) at 72° F. The 3″-wideelastomeric joint tape prepared in this example is capable ofwithstanding greater than the expected normal movement of 4′×8′ fibercement panels.

The 180° peel strength of this tape was about 10 lb/inch at 72° F. At120° F., the 180° peel strength was reduced to about 4.7 lb/inch. Underwater saturation conditions, the 180° peel strength was about 10 lb/inchat 72° F. This joint tape has better heat and water resistance than theMulticoat tape used in EXAMPLE 5.

The joint tapes made according to the present disclosure produce a jointthat is more resistant to cracking than one produced with the commercialtape at identical tape widths. The selected adhesives endow thedisclosed joint tapes with superior heat and water resistance comparedto the commercial joint tape. Because the normal expected movement of4′×8′ fiber cement panels is 3–5 mm or more (3.9–6.6% for a 3″-widetape), and because a standard joint tape is about 3″ wide, anelastomeric joint preferably withstands greater than 6.6% stretchingwithout cracking, more preferably from about 6.6% to about 20%stretching, wherein the preferred range includes stretching values of7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, and 20%.

The 180° peel strength at 72° F. is preferably about 10 lb/in orgreater, more preferably about 10.3 lb/in or greater, most preferablyabout 10.6 lb/in or greater. At 120° F., the 180° peel strength ispreferably about 2 lb/in or greater, more preferably about 4 lb/in orgreater, most preferably about 6 lb/in or greater. Under watersaturation conditions at 72° F., the 180° peel strength is preferablyabout 5 lb/in or greater, more preferably, about 6 lb/in or greater,most preferably about 7 lb/in or greater.

Method 2

FIG. 16 illustrates METHOD 2 of making an elastomeric joint, which doesnot use an adhesive tape. A pressure-sensitive adhesive is applied tothe edges of the front surface of building panels and a release linerlaminated to the adhesive, producing adhesive-edge panels. A preferredembodiment of an adhesive-edge panel is illustrated in FIG. 31A and FIG.31B, which has a panel 910, a first adhesive 930, a second adhesive 940,and a release liner 990. In METHOD 2, the first adhesive and the secondadhesive are the same adhesive. The adhesive and release liner may bepre-applied by the panel manufacturer. The backing material is appliedto the adhesive panels during wall installation. Steps 1610 and 1620describe the manufacture of an adhesive-edge panel. Steps 1630, 1640,and 1650 describe making an elastomeric joint using the adhesive-edgepanels.

In step 1610, an adhesive layer is applied along an edge of the frontsurface of a building panel. Specifications for the adhesive and methodsof applying the adhesive are as described above. Preferably, theadhesive is applied around the perimeter of the front surface of thebuilding panel. The width of the adhesive layer is preferably aboutone-half the width of the backing material, and may be adjusted to takeinto account any gaps to be left between adjacent panels or variabilityin the width of the backing material. The width of the adhesive layermay also be greater than one-half the width of the backing material toassure that the edges of the backing material are completely adhered tothe panel and to allow for small misalignments in the installation ofthe backing material. An adhesive layer that is too wide increasesamount of adhesive and release liner used, however, increasing the cost.Furthermore, foreign materials could potentially adhere to any adhesivethat is not covered by the backing material, possibly affecting theappearance or adhesion of the finish layer. In a preferred embodimentfor making a 3″-wide joint, an adhesive layer of from about 1⅜″ to about1 9/16″, more preferably about 1 7/16″ wide is applied at each edge.

In step 1620, a paper or plastic film coated with a release agent islaminated to the adhesive layer on the building panel. Thespecifications for the release liner are provided above. In step 1630,the panels are installed with the adhesive-coated faces facing outwardsas described above. If gaps were left between the building panels, instep 1640, the gaps are optionally caulked as described above.

In step 1650, the release liner is removed from the adhesive and abacking material is applied to the adhesive. Preferably, the backingmaterial is centered over the joint. Suitable backing materials aredescribed above.

EXAMPLE 8

A piece of 1 7/16″×2″×0.015″ PL515 adhesive (SIA Adhesives) was appliedto an edge of the upper surface of each of two 2″×5″ primed fiber cementspecimens (James Hardie, Fontana, Calif.). A sheet of silicone-basedrelease liner was applied over the adhesive on each fiber cementspecimen. The adhesive-coated edges were arranged face-up and adjacent,leaving a ⅛″ gap between the specimens. The joint was caulked and thecaulk cured as described in EXAMPLE 5. Then the release liner was fromthe adhesive on the fiber cement specimens. A 2″×3″ piece of Sontara8000 fabric (Dupont) was centered and applied to the adhesive. The testsample was finished and cured as described for EXAMPLE 5.

Under tensile testing at 6 mm/min, the texture coating did not crackuntil the joint was stretched about 12 mm (15.7%) at 72° F. The 3″-wideelastomeric joint prepared in this example is capable of withstandinggreater than the expected normal movement of 4′×8′ fiber cement panels.

Method 3

FIG. 17 illustrates METHOD 3 for making an elastomeric joint, in whichneither an adhesive tape nor an adhesive panel is prefabricated.Instead, a flexible adhesive layer is applied either to the buildingpanel or to the backing material after the panels have been installedonto a frame. The adhesive may be pressure sensitive or non-pressuresensitive. Preferably, the adhesive is non-pressure sensitive, resultingin a more durable joint. Typically, non-pressure-sensitive adhesives aremore heat and water resistant than pressure-sensitive adhesives. Theadhesive layer may be pre-made as a double-sided tape or an adhesivepaste. In any case, the adhesive should distribute movement of thepanels to the entire backing material, yet not slip from the panel atthe edges of the backing material.

In step 1710, the panels are installed as described above. In step 1720,the panels are caulked as described above.

In step 1730, an adhesive layer is be applied either to the adjacentedges of the panels or to a backing material. Suitable adhesives andmethods of applying the adhesive are described above. Preferredadhesives may be the same as or different from the preferred adhesivesused in METHOD 1 or METHOD 2.

In step 1740, either the backing material is applied to theadhesive-covered edges of the panels or the adhesive-coated backingmaterial to the center of the joint. A suitable backing material isselected as described above. If the adhesive is not a pressure-sensitiveadhesive, this step is preferably completed before the adhesive curesexcessively.

EXAMPLE 9

Two 2″×5″ pre-coated fiber cement board specimens (James Hardie,Fontana, Calif.) were arranged with a ⅛″ gap between them. The gap wascaulked with a 100% polyurethane caulk (Chem-calk 900, Bostik Findley)and the caulk surface smoothed. In this example, the caulk was also usedas the adhesive. A 0.01 ″ layer of the same caulk was applied to a 2″×3″area centered on the joint. A 2″×3″ piece of Sontara 8004 fabric(Dupont) was applied over the caulking. The test sample was finished andthe finish cured as described in EXAMPLE 5.

Under tensile testing at 6 mm/min, the texture coating did not crackuntil the joint was stretched about 5.2–6.9 mm (6.8–9.1%) at 72° F.

Multiple adhesives may be used in the disclosed elastomeric jointsystem. In one embodiment, a first adhesive, applied at the center ofthe joint, is an elastomeric material that slips with the movement ofthe panels, distributing the movement to the entire backing material. Asecond adhesive, used at the edges of the joint, is relatively rigid,anchoring the edges of the backing material to the panel. An elastomericjoint made according to this method can withstand large relative panelmovements without cracking the finish coating at any part of the joint,including the edges.

Method 4

FIG. 30 illustrates a preferred embodiment of a joint tape 3000 madefrom a backing material 950, a first adhesive 930, a second adhesive940, and an optional release liner 990. FIG. 18 illustrates METHOD 4,which like METHOD 1 uses a prefabricated adhesive joint tape. The jointtape may be prefabricated by a tape manufacturer. Unlike METHOD 1, thejoint tape of METHOD 4 uses two adhesives, a first adhesive 930 used inthe center, which is relatively elastomeric, and a second adhesive 940used at the edges, which is relatively rigid. Preferred adhesives arepressure sensitive. For a 3″-wide tape, a preferred width of adhesive930 is from about 0″ to about 3″ and a preferred width of adhesive 940is from about 0″ to about 3″.

The steps of METHOD 4 are substantially the same as for METHOD 1. Theprincipal difference between METHOD 4 and METHOD 1 is that METHOD 4 usestwo adhesives where METHOD 1 uses a single adhesive.

A joint tape is made in steps 1810 and 1820. In step 1810, a firstadhesive 930 and a second adhesive 940 are applied to a backing material950. In step 1820, a release liner is optionally laminated to theadhesives.

In steps 1830, 1840 and 1850, the joint tape is applied to the seambetween adjacent building panels to produce an elastomeric joint. Instep 1830, building panels are installed as described above. In step1640, caulk is optionally applied between the building panels, asdescribed above. In step 1850, the release liner is removed from theelastomeric joint tape and the exposed adhesive face of the joint tapeis applied over the joint between the panels. The joint tape ispreferably centered over the joint.

EXAMPLE 10

A tape was made with PVT-3300 (Carlisle Coating & Waterproofing) and HL2203 (H.B. Fuller) pressure sensitive adhesives. A 2½″-wide×0.028″-thicklayer of PVT-3300 adhesive was applied to the center of a 3″-wide stripof Sontara 8000 fabric (Dupont). A ¼″-wide×0.002″-thick layer of HL 2203adhesive was applied to both edges of the fabric. Two 2″×5″ primed fibercement specimens (James Hardie, Fontana, Calif.) were butted togetherwith no gap and no caulk. A 2″×3″ piece of the elastomeric tape wascentered over the seam and applied to the panels. The test sample wasfinished and the finish cured as described in EXAMPLE 5.

Under tensile testing at 6 mm/min, the texture coating did not crackuntil the joint was stretched about 12–13 mm (15.7–17.1%) at 72° F. The3″-wide elastomeric joint tape prepared in this example is capable ofwithstanding greater than the expected normal movement of 4′×8′ fibercement panels.

EXAMPLE 11

The experiment of EXAMPLE 10 was repeated except that the tape was madewith only the elastomeric first adhesive. In this example, a3″-wide×0.028″-thick layer of PVT-3300 pressure sensitive adhesive wasused to make the joint tape. No H2203 adhesive was used at the edge.Under the same test conditions, the texture coating cracked at the edgeof the fabric when the joint was stretched about 3–4 mm (3.9–5.2%) at72° F.

EXAMPLE 10 and EXAMPLE 11 demonstrate the advantages of a dual-adhesivesystem compared to a similar single-adhesive system.

Note that in EXAMPLE 10 and EXAMPLE 11, the elastomeric joint isfabricated without caulk, i.e., the joint is a caulkless elastomericjoint. This caulkless joint has several advantages over a joint madewith caulk. First, omitting the caulk is less expensive because one neednot obtain the caulk. Second, the caulkless method saves the timerequired to apply the caulk as well as the time required for the caulkto cure. Third, the caulkless method is simpler, both because one neednot apply any caulk, and because the panels may be butted together,eliminating the step of positioning the panels with gaps.

Method 5

FIG. 19 illustrates METHOD 5 of making an elastomeric joint. As inMETHOD 1 and METHOD 4, a joint tape is prefabricated, then applied tothe joint. In a preferred embodiment, the joint tape is pre-made by atape manufacturer. Unlike the joint tape of METHOD 4, which is a dualadhesive tape, the joint tape of METHOD 5 is a single adhesive tape. Theadhesive 930 in the joint tape of METHOD 5 is pre-applied down thecenter of the backing material, with no adhesive at the edges. Thesecond adhesive 940 is applied during the installation of the wallsystem either to the backing material or to the building panels.

In an alternative embodiment, the joint tape is prefabricated with thesecond adhesive 940 applied to the edges of the backing material. Inthis embodiment, the first adhesive 930 is applied during theinstallation of the wall system either to the center of the bakingmaterial or to the building panels.

Preferably, the adhesive applied to the backing material in the jointtape manufacturing process is pressure sensitive. The adhesive appliedduring the installation of the wall system may be pressure sensitive ornon-pressure sensitive. More preferably, the joint tape is manufacturedwith the first adhesive 930, the more elastomeric adhesive, applied downthe center of the backing material. In this embodiment, the secondadhesive 940 is preferably a non-pressure-sensitive adhesive because awider range of non-pressure-sensitive adhesives produce the desiredstrong bond between the panel and the edges of the backing material. Fora 3″-wide tape, the preferred width of adhesive 930 is from about 0″ toabout 3″, and the preferred width of adhesive 940 is from about 0″ toabout 3″, wherein the sum of the widths of the two adhesives is 3″. Thefollowing procedure describes an embodiment in which the first adhesive930 is used to manufacture the joint tape.

The joint tape is manufactured in steps 1910 and 1920. In step 1910,first adhesive 930 is applied down the center of the backing material950. Selection of adhesive and the backing material, and application ofthe adhesive is described above. In step 1920, a release liner isoptionally laminated to the adhesive.

In step 1930, building panels are installed as described above. In step1940, caulk is optionally applied between the building panels, asdescribed above. In step 1950, second adhesive 940 is applied to thepanel at a location corresponding to the edges of the installed backingmaterial or applied to the edges of the backing material of the jointtape manufactured in steps 1910 and 1920. The second adhesive 940 isapplied as described above. Preferably, the second adhesive 940 isnon-pressure sensitive. The second adhesive 940 may be applied eitherbefore or after the joint tape has applied to the joint.

EXAMPLE 12

A 2½″-wide×0.028″-thick layer of PVT-3300 pressure sensitive adhesive(Carlisle Coating & Waterproofing) was applied down the center of a2″×3″ piece of Sontara 8000 fabric (Dupont), leaving about a ¼″ of each2″ edge of the fabric was free of adhesive. Two 2″×5″ specimens ofprimed fiber cement panels were butted together, leaving no gap. Nocaulk was applied. The elastomeric joint tape was centered and appliedto the joint. To each edge of the backing material was applied a¼″-wide×0.002″-thick layer of UR-0210 moisture-cured polyurethane (H.B.Fuller), and the edges applied to the panels. The test sample wasfinished and the finish cured as described in EXAMPLE 5.

Under tensile testing at 6 mm/min, the texture coating did not crackuntil the joint was stretched about 12–13 mm (15.7–17.1%) at 72° F. At120° F., the texture coating cracked when the joint was stretched 13 mm(17.1%), indicating the heat resistance of the joint. The 3″-wideelastomeric joint tape prepared in this example is capable ofwithstanding greater than the expected normal movement of 4′×8′ fibercement panels.

The Sontara fabrics (Dupont) work well as the backing material, althoughother stretchable fabrics are also suitable. The experiment in EXAMPLE12 was repeated with a polyamide (Nylon) fabric in EXAMPLE 13.

EXAMPLE 13

A 2½″-wide×0.028″-thick layer of PVT-3300 pressure sensitive adhesivewas applied down the center of a 3″-wide piece of Nylon mesh P2017(Applied Extrusion Technologies), leaving about a ¼″ of each 2″ edge ofthe fabric was free of adhesive. Two 2″×5″ specimens of primed fibercement panels were butted together, leaving no gap. No caulk wasapplied. The elastomeric joint tape was centered and applied to thejoint. To each edge of the backing material was applied a¼″-wide×0.002″-thick layer of UR-0210 moisture-cured polyurethane (H.B.Fuller), and the edges applied to the panels. The test sample wasfinished and the finished cured as described in EXAMPLE 5.

Under tensile testing at 6 mm/min, the texture coating did not crackuntil the joint was stretched about 7–11 mm (9.2–14.4%) at 72° F. The3″-wide elastomeric joint tape prepared in this example is capable ofwithstanding greater than the expected normal movement of 4′×8′ fibercement panels.

Non-stretchable and semi-stretchable fabrics such as non-woven glassfiber fabric that were tested were unable to withstand large jointmovements. A representative test is provided in EXAMPLE 14.

EXAMPLE 14

A 2½″-wide×0.028″-thick layer of PVT-3300 pressure sensitive adhesive(Carlisle Coating & Waterproofing) was applied down the center of a3″-wide piece of non-woven glass-fiber fabric (M524-C33, Owens Corning)leaving about a ¼″ of each 2″ edge of the fabric was free of adhesive.Two 2″×5″ specimens of primed fiber cement panels were butted together,leaving no gap. No caulk was applied. The elastomeric joint tape wascentered and applied to the joint. To each edge of the backing materialwas applied a ¼″-wide×0.002″-thick layer of UR-0210 moisture-curedpolyurethane (H.B. Fuller), and the edges applied to the panels. Thetest sample was finished and the finish cured as described in EXAMPLE 5.

Under tensile testing at 6 mm/min, the texture coating cracked when thejoint was stretched about 1.8 mm (2.4%) at 72° F. The 3″-wide joint tapeprepared in this example is incapable of withstanding greater than theexpected normal movement of 4′×8′ fiber cement panels.

Method 6

FIG. 20 illustrates METHOD 6 of making an elastomeric joint, which issimilar to METHOD 5, except that the second adhesive 940 is not appliedto the backing material or panels in a step analogous to step 1950 ofMETHOD 5. Instead, METHOD 6 uses a backing material that allows thefinish coating to permeate the fabric and to bond to the buildingpanels. As such, the finish coating serves as the second adhesive 940,eliminating a separate application step. For a 3″-wide tape, thepreferred width of adhesive 930 is from about 0″ to about 3″.

In step 2010, first adhesive 930 is applied down the center of thebacking material 950. The backing material is permeable to theelastomeric finish coat. Selection and application of the adhesive isdescribed above. In step 1820, a release liner is optionally laminatedto the adhesive 930.

In step 2030, building panels are installed as described above. In step2040, caulk is optionally applied between the building panels, asdescribed above. In step 2050, the release liner is removed from theelastomeric joint tape and the exposed adhesive face of the joint tapeis applied over the joint between the panels. The joint tape ispreferably centered over the joint. In step 2060, an elastomeric finish980 is applied to the panelized wall system. The finish permeates thebacking material 950, functioning as the second adhesive 940.

In alternative embodiment of METHOD 6, a strip of the first adhesive 930that is narrower than the backing material is applied to adjacent edgesof the building panels. A backing material that is permeable to theelastomeric finish coating is then centered and applied to the joint,leaving the edges of the backing material free of adhesive. The texturecoating applied to the entire wall permeates the backing material,functioning as the second adhesive 940. For 3″-wide backing material,the preferred width of adhesive 930 is from about 0″ to about 3″. Wherethe first adhesive 930 is 3″-wide, the same width as the backingmaterial, METHOD 6 is the same as METHOD 1.

EXAMPLE 15

A 2½″-wide×0.028″-thick layer of PVT-3300 pressure sensitive adhesive(Carlisle Coating & Waterproofing) was applied down the center of a3″-wide piece of Sontara 8801 fabric (Dupont), leaving about a ¼″ ofeach 2″ edge of the fabric was free of adhesive. Two 2″×5″ specimens ofprimed fiber cement panels were arranged with a ⅛″ gap. No caulk wasapplied to the gap. The elastomeric joint tape was centered and appliedto the joint. The test sample was finished and the finish cured asdescribed in EXAMPLE 5.

Under tensile testing at 6 mm/min, the texture coating did not crackuntil the joint was stretched about 9–13 mm (11.8–17.1%) at 72° F. The3″-wide elastomeric joint tape prepared in this example is capable ofwithstanding greater than the expected normal movement of 4′×8′ fibercement panels.

Method 7

FIG. 21 illustrates METHOD 7 for making an elastomeric joint, which issimilar to METHOD 2 in that an adhesive joint tape is not pre-made.Instead, pressure-sensitive adhesives are applied to the edges of thefront faces of the building panels and a release liner is laminated tothese adhesive-edge panels. The adhesive-edge panels may beprefabricated by the panel manufacturer. After the panels are fastenedto the frame, the backing material is applied to the adhesive ofadjacent panels. A preferred embodiment of an adhesive-edge panel isillustrated in FIG. 31A and FIG. 31B, which has a panel 910, a firstadhesive 930, a second adhesive 940, and a release liner 990. UnlikeMETHOD 2, which uses a single adhesive, METHOD 7 uses two adhesives, amore elastomeric first adhesive 930, applied at the center of the joint,and a more rigid second adhesive 940, applied at the edges of the joint.Preferably, both adhesives 930 and 940 are pressure sensitive.

For a 3″-wide backing material, the preferred width of adhesive 930 oneach panel is from about 0″ to about 1½″ and the preferred width ofadhesive 940 on each panel is from about 0″ to about 1½″, wherein thesum of the widths is about 1½″. As would be apparent to one skilled inthe art, the sum of the widths may be smaller if adjacent panels areinstalled with a gap. METHOD 7 is the same as METHOD 2 if the width ofeither the first adhesive 930 or the second adhesive 940 is 0″.

In step 2110, a first adhesive 930 is applied along an edge of the frontsurface of a building panel and a second adhesive 940 is appliedadjacent to the first adhesive 930, away from the edge of the panel.Specifications for the adhesives and methods of applying the adhesiveare as described above. Preferably, the adhesive is applied around theperimeter of the front surface of the building panel. In a preferredembodiment, the total width of the adhesive layers is about 1 7/16″ wideat the edge for making a 3″-wide elastomeric joint.

In step 2120, a release liner is laminated to the adhesive layer on thebuilding panel. The specifications for the release liner are providedabove.

In step 2130, the panels are installed with the adhesive-coated facesfacing outwards as described above. In step 2140, the gaps between theinstalled building panels are optionally caulked as described above. Instep 2150, the release liner is removed and the backing material isapplied to the exposed adhesive. Preferably, the backing material iscentered over the joint. Suitable backing materials are described above.

EXAMPLE 16

The same methods and materials used in EXAMPLE 10 (METHOD 4) were usedin EXAMPLE 16, except that the adhesives were applied to the fibercement panels instead of to the backing material. Under tensile testingat 6 mm/min, the texture coating did not crack until the joint wasstretched about 12–13 mm (15.7–17.1%) at 72° F. The 3″-wide elastomericjoint prepared in this example is capable of withstanding greater thanthe expected normal movement of 4′×8′ fiber cement panels.

Method 8

FIG. 22 illustrates METHOD 8 of making an elastomeric joint, which issimilar to METHOD 7 except that only one adhesive is pre-applied to thebuilding panels. The adhesive may be pre-applied by the panelmanufacturer.

In METHOD 8, a first adhesive 930 is applied to the part of the edge onthe front face of a panel that will become the center of the joint. Thesecond adhesive 940 is applied either to the backing material or to thepart of the panel corresponding to the edge of the joint during wallinstallation. In another embodiment, the second adhesive 940 ispre-applied to the panel before installation, and first adhesive 930 isapplied to the backing material or to the panel during the wallinstallation. Preferably, the pre-applied adhesive is pressuresensitive. The later applied adhesive may be pressure sensitive ornon-pressure sensitive. More preferably, first adhesive 930 is thepre-applied adhesive and second adhesive 940 is the later appliedadhesive. In this embodiment, the second adhesive 940 is preferably anon-pressure-sensitive adhesive because a wider range ofnon-pressure-sensitive adhesives produce the desired strong bond betweenthe panel and the edges of the backing material. For a 3″-wide joint,the preferred width of the first adhesive 930 on each panel is fromabout 0″ to 1½″, and the preferred width of the second adhesive 940 oneach panel is about 0 to 1½″, wherein the sum of the widths about 1½″.

In step 2210, a first adhesive 930 is applied along an edge of the frontsurface of a building panel to an area corresponding to the center ofthe joint. Specifications for the adhesives and methods of applying theadhesive are as described above. Preferably, the adhesive is appliedaround the perimeter of the front surface of the building panel. In apreferred embodiment, the total width of the adhesive layers is about 17/16″ wide at the edge for making a 3″-wide elastomeric joint.

In step 2220, a release liner is laminated to the adhesive layer on thebuilding panel. The specifications for the release liner are providedabove.

In step 2230, the panels are installed with the adhesive-coated facesfacing outwards as described above. In step 2240, the gaps between theinstalled building panels are optionally caulked as described above. Instep 2250, a second adhesive 940 is applied to the edges of a backingmaterial 950 or to the portion of the panel corresponding 910 to theedge of the joint. In step 960, the release liner is removed and thebacking material is applied to the exposed adhesive. Preferably, thebacking material is centered over the joint. Suitable backing materialsare described above.

In an alternative embodiment, the second adhesive 940 is applied in step2010 to the area on an edge of the panel 910 corresponding to the edgeof the joint. In step 950, the first adhesive 930 is applied to eitherthe center of the backing material 950 or to the portion of the panel 910 corresponding to the center of the joint.

Method 9

FIG. 23 illustrates METHOD 9 of making an elastomeric joint, which issimilar to METHOD 3 in that adhesive is not pre-applied either to thebacking material or to the panels. The difference between METHOD 9 andMETHOD 3 is that METHOD 9 uses two adhesives while METHOD 3 uses asingle adhesive. The adhesives may be applied either to the backingmaterial or to the panels. Either adhesive layer may be made into adouble-side tape or an adhesive paste. In another embodiment, bothadhesives are incorporated into a single double-sided tape. For a3″-wide joint, the preferred width of the first adhesive 930 is fromabout 0″ to about 3″ and the preferred width of the second adhesive 940is from about 0″ to about 3″, wherein the sum of the widths of the twoadhesives is about 3″.

In step 2310, the panels are installed as described above. In step 2320,caulk is optionally applied to any gaps left between the panels.

In step 2330, a first adhesive 930 and a second adhesive 940 are appliedto a backing material 950 or to the area of the panels 910 correspondingto the joint. In either case, the first adhesive 930 is applied to thearea corresponding to the center of the joint and the second adhesive isapplied to the area corresponding to the edges of the joint. The firstadhesive 930 may be applied before, after, or at same time as the secondadhesive 940.

In step 2340 the backing material with the preapplied adhesive isapplied to the joint between adjacent panels, or a backing material isapplied to the adhesive that was preapplied to the panels. Preferably,the backing material is centered over the joint in either case.

EXAMPLE 17

Two 2″×5″ specimens of primed fiber cement panels were arranged with a⅛″ gap between them. The gap was caulked and the caulk cured asdescribed in EXAMPLE 5. A 2½″-wide×0.02″-thick layer of HL2203 adhesive(H.B. Fuller) was applied to the panels centered on the joint. A1/4″-wide×0.002″-thick layer of UR-0210 moisture-cured polyurethaneadhesive (H.B. Fuller) was applied on the panels on each side of theHL2203 adhesive. A 2″×3″ piece of Sontara 8000 fabric was applied to theadhesives. The test sample was finished and the finish cured asdescribed in EXAMPLE 5.

Under tensile testing at 6 mm/min, the texture coating did not crackuntil the joint was stretched about 16 mm (21.0%) at 72° F. The 3″-wideelastomeric joint prepared in this example is capable of withstandinggreater than the expected normal movement of 4′×8′ fiber cement panels.

Method 10

FIG. 24 illustrates METHOD 10 of making an elastomeric joint, which usesboth an adhesive joint tape and adhesive-edge panels. The first adhesive930 is pre-applied either to the backing material or to an edge of thefront of the panel. The second adhesive 940 is pre-applied to an edge ofthe front of the panel if the first adhesive is pre-applied to thebacking material, or to the backing material if the first adhesive ispre-applied to a edge of the front of the panel. Both adhesives arepreferably pressure sensitive. For a 3″-wide joint, the preferred widthof the first adhesive 930 is from about 0″ to about 3″ and the preferredwidth of the second adhesive 940 is from about 0″ to about 3″, whereinthe sum of the widths of both adhesives is about 3″. METHOD 10 is thesame as METHOD 4 if both adhesives are pre-applied to the backingmaterial and METHOD 7 if both adhesives are pre-applied to the frontedges of the building panel.

In step 2410, a first adhesive 930 is applied down the center of thebacking material 950. In step 2420, a release liner is optionallylaminated to the first adhesive.

In step 2430, a second adhesive is applied to an area of a panel 910corresponding to the edge of the joint. In step 2440, a release liner islaminated to the second adhesive.

In step 2450, the adhesive-edge building panels produced in steps 2430and 2440 are installed as described above. In step 2460, caulk isoptionally applied between any gaps between the panels. In step 2470,the release liners are removed from the panels and the joint tape, andthe joint tape is applied to the joint. Preferably, the joint tape iscentered over the joint.

Method 11

An elastomeric joint fabricated according to METHOD 11 is illustrated inFIG. 25. Elastomeric joint 900 includes two building panels 910, aflexible first adhesive layer 930, rigid second adhesive layers 940, abacking material 950, and a joint filler 970. The panels and elastomericjoint are optionally finished with a texture coating 980. The panels 910illustrated in FIG. 25 have embossed edges and trough edges 960;however, flat panels as well as panels with only embossed edges may alsobe used in this method. In METHOD 11, an elastomeric joint constructedaccording to any of METHOD 1 through METHOD 10 is covered with a jointfiller 970. In the embodiment illustrated in FIG. 25, substantially nogap is provided between the panels 910, and accordingly, no caulk isused.

FIG. 26 illustrates METHOD 11 of constructing an elastomeric joint. Instep 2610, an elastomeric joint is fabricated at the joint betweenadjacent building panels according to any of METHOD 1 through METHOD 10.In step 2620, a layer of joint filler 970 is applied to cover thebacking material 950. In a preferred embodiment, the joint filler 970 isa ceramic putty.

The joint filler 970 simplifies the production of a panelized wall witha monolithic appearance. The joint filler provides another component inthe elastomeric joint system for distributing the relative movements ofadjacent panels. As is well known in the are, the joint filler may beused to cover the edges of the backing material as well as to fill anydepressions in the joint or trough areas, providing a smooth surface forsubsequently applied texture coatings. The joint filler may be tooledduring application or may be sanded after curing to provide a smoothsurface. As illustrated in FIG. 25, METHOD 11 is a preferred method whenused in conjunction with trough-edge panels. Moreover, METHOD 11 isadvantageously applied to wall systems constructed from panels withembossed edges or other edge profiling because the depth of theembossing need not closely match the total thickness of the backingmaterial and adhesive. Also the width of the embossing need not closelymatch the width of the backing material, especially important becausethe panels may be installed either without gaps or with gaps of varyingwidth. METHOD 11 is also advantageously be used with flat-edge orplain-edge panels.

In a preferred embodiment of METHOD 11, a second joint filler,preferably an elastomeric joint filler, is applied over the first jointfiller, as described above.

FIG. 27 is an elevation view of a panelized wall system 2700 composed ofa frame 2710, building panels 2720, elastomeric joints 2730, andfasteners 2740.

FIG. 28 illustrates the construction of a panelized wall systemaccording to METHOD 11. In step 2810, the back surfaces of buildingpanels 2720 are positioned over a frame 2710 as described above. Thebuilding panels are preferably fiber cement, and may be flat, havetrough edges, or embossed edges. The frame is optionally equipped with amoisture barrier, for example asphalt paper, a water break, or both. Thepanels are positioned over the optional moisture barrier and waterbreak. The panels may be positioned with gaps between adjacent panels orbutted, i.e., with no gaps between adjacent panels, ad described above.

In step 2820, the panels 2720 are attached to the frame 2710 withfasteners 2740 as described above. If gaps were left between adjacentpanels in step 2810, in step 2830, caulk is optionally applied to fillthe gaps. In step 2840, a backing material is adhered to the jointsbetween the panels 2720. Steps 2810–2840 may be performed according toany of METHOD 1 to METHOD 10.

In step 2850, a joint filler is optionally applied over the backingmaterial, as described above. In step 2860, an elastomeric finish isapplied to the entire panelized wall system as described above.

EXAMPLE 18

A wall was framed with 2″×4″ lumber, studs 16″-on-center. Asphalt paperand a water break (Homeslicker Rain Screen, Benjamin Obdyke, Horsham,Pa.) were installed on the frame. The back surfaces of 4′×8′×⅝″trough-edge fiber-cement panels were positioned over the frame level andplumb, with the edges of adjacent panels sharing a stud. That troughdepth was 0.077″, the trough-edge offset was 1½″, and the trough widthwas ¾″. The edges of the panels butted together leaving no gaps. Thepanels were nailed to the frame. The joints between the panels weretaped with a tape made from 3″-wide Sontara 8804 fabric (DuPont) and a0.010″-thick layer of Heartland Adhesive H400 (styrene-butadiene). Thetaped joints were then covered with a smooth, flat layer of a ceramicputty joint filler (Fill-n-Build, Global Coatings), which was allowed tocure for 1 to 2 hours. The joint filler was then covered with a smooth,flat layer of an elastomeric joint filler (Acracream, Global Coatings).The wall was allowed to cure for a minimum of about 24 hours.

A stucco covering was then applied to the wall. First, Colorseal PlusPrimer (Global Coatings) was applied to the entire wall surface with apaint roller and allowed to dry for 1 to 2 hours. Next, Carrara texture(Global Coatings) was shot onto the wall with a hopper gun. At thispoint, the surface may be left “as is” for a “sanded” finished orhand-troweled to the desired finish. The stucco finish was protecteduntil cured.

EXAMPLE 19

A panelized wall was constructed according to EXAMPLE 18 except that theframe included 4′×8′×½″ OSB shear panels attached to the studs, followedby the asphalt paper and the water break.

EXAMPLE 20

The comparative performances in a racking test of a wall constructedaccording to the preferred method disclosed in U.S. Pat. No. 5,732,520and a wall constructed according to the present disclosure wereevaluated in this test.

The test walls were constructed in a testing device as described in ASTME 72-(98). The walls were 8′×8′ walls framed with 2″×4″ lumber, studs16″-on-center. Two fiber-cement panels with plain edges, 4′×8′× 5/16″(Hardiepanel, James Hardie, Fontana, Calif.), were positioned on theframe, their adjacent edges sharing a stud with a ⅛″ gap between them.The panels were attached to the frame. The gap between the panels wascaulked with Chem-calk 900 (Bostik Findley), the surface of the caulksmoothed, and the caulk allowed to cure overnight. The joints were thentaped with either the joint tape of U.S. Pat. No. 5,732,520 or a jointtape according to the present disclosure. The joints were finished witha smooth stucco coating (Multitex, Multicoat, Costa Mesa, Calif.).Finally, both walls and joints were finished with a medium texturestucco coating (Multitex, Multicoat, Costa Mesa, Calif.).

The joint tape of U.S. Pat. No. 5,732,520 is a commercially available3″-wide wide self-adhesive joint tape (Multicoat, Costa Mesa, Calif.)made from a fabric backing and a pressure sensitive adhesive. The jointtape of the present disclosure is a 3″-wide self-adhesive joint tapemade from Sontara 8004 fabric and a 0.010″-thick layer of HeartlandAdhesive H400 (styrene-butadiene).

Each wall was subjected to a racking load according to the test method.The results are provided in FIG. 29. The wall constructed according tothe disclosed method withstood a higher racking load and deflectionbefore cracking at the panel joints.

The embodiments illustrated and described above are provided as examplesof certain preferred embodiments of the present invention. Variouschanges and modifications can be made to the embodiments presentedherein by those skilled in the art without departure from the spirit andscope of this invention, the scope of which is limited only by theclaims appended hereto.

1. A method of constructing a caulkless panelized wall system,comprising: positioning at least two building panels over a frame,wherein the at least two building panels are substantially cementitious,each panel comprises a front surface, a back surface, and a plurality ofedges, the back surfaces of the panels are positioned over the frame,the two panels are positioned adjacent to each other, forming a seambetween the adjacent panels, and the two panels are substantiallycoplanar; fastening the panels to the frame; and forming a caulklesselastomeric joint comprising a backing material adhered over the seam,wherein the backing material is adhered to the front surfaces of theadjacent panels without any caulk applied to the seam between theadjacent panels.
 2. The method of claim 1, wherein the panels are fibercement.
 3. The method of claim 1, wherein the adjacent panels arepositioned with no gap therebetween.
 4. The method of claim 1, whereinthe adjacent panels are positioned with a gap therebetween.
 5. Themethod of claim 4, wherein the gap is about ⅛″ wide.
 6. The method ofclaim 1, wherein the backing material is a fabric.
 7. The method ofclaim 6, wherein the backing material is from about 0.0005″ to about0.04″ thick.
 8. The method of claim 6, wherein the fabric is a non-wovenpolyester fabric.
 9. The method of claim 6, wherein the fabric is apolyamide mesh.
 10. The method of claim 1, wherein the backing materialis about 3″ wide.
 11. The method of claim 1, wherein the backingmaterial is applied as a joint tape, wherein the joint tape comprises anadhesive preapplied to a face of the backing material.
 12. The method ofclaim 1, wherein the caulkless elastomeric joint further comprises aceramic putty applied over the backing material.
 13. The method of claim12, wherein the caulkless elastomeric joint further comprises anelastomeric joint filler applied over the ceramic putty.
 14. The methodof claim 1 further comprising applying an elastomeric finish to thepanelized wall system.
 15. The method of claim 14, wherein theelastomeric finish comprises an elastomeric primer and an elastomerictexture layer.
 16. The method of claim 14, wherein the elastomericfinish is a texture coating.
 17. The method of claim 1, wherein theframe is a wood frame.
 18. The method of claim 1, wherein the framecomprises shear panels.
 19. The method of claim 1, wherein the framecomprises a moisture barrier.
 20. The method of claim 1, wherein theframe comprises a water break.
 21. A caulkless panelized wall systemcomprising a frame; at least two building panels positioned over theframe, wherein the at least two building panels are substantiallycementitious; each panel comprises a front surface, a back surface, anda plurality of edges, the back surfaces of the panels are positionedover the frame, the two panels are positioned adjacent to each other,forming a seam between the adjacent panels with no caulk applied to theseam, the panels are fastened to the frame, and no caulk is applied tothe seam; and a caulkless elastomeric joint comprising a backingmaterial adhered over the seam between the adjacent panels, wherein thebacking material is adhered to the front surfaces of the adjacent panelswithout any caulk applied to the seam between the adjacent panels. 22.The caulkless panelized wall system of claim 21, wherein the panels arefiber cement.
 23. The caulkless panelized wall system of claim 21,wherein the adjacent panels are positioned with no gap therebetween. 24.The caulkless panelized wall system of claim 21, wherein the adjacentpanels are positioned with a gap therebetween.
 25. The caulklesspanelized wall system of claim 24, wherein the gap is about ⅛″ wide. 26.The caulkless panelized wall system of claim 21, wherein the backingmaterial is a fabric.
 27. The caulkless panelized wall system of claim26, wherein the backing material is from about 0.0005″ to about 0.04″thick.
 28. The caulkless panelized wall system of claim 26, wherein thefabric is a non-woven polyester fabric.
 29. The caulkless panelized wallsystem of claim 26, wherein the fabric is a polymamide mesh.
 30. Thecaulkless panelized wall system of claim 21, wherein the backingmaterial is about 3″ wide.
 31. The caulkless panelized wall system ofclaim 21, wherein the backing material is applied as a joint tape,wherein the joint tape comprises an adhesive preapplied to a face of thebacking material.
 32. The caulkless panelized wall system of claim 21,wherein the caulkless elastomeric joint further comprises a ceramicputty applied over the backing material.
 33. The caulkless panelizedwall system of claim 32, wherein the caulkless elastomeric joint furtheran elastomeric joint filler applied over the ceramic putty.
 34. Thecaulkless panelized wall system of claim 21 further comprising applyingan elastomeric finish to the panelized wall system.
 35. The caulklesspanelized wall system of claim 34, wherein the elastomeric finishcomprises an elastomeric primer and an elastomeric texture layer. 36.The caulkless panelized wall system of claim 34, wherein the elastomericfinish is a texture coating.
 37. The caulkless panelized wall system ofclaim 21, wherein the frame is a wood frame.
 38. The caulkless panelizedwall system of claim 21, wherein the frame comprises shear panels. 39.The caulkless panelized wall system of claim 21, wherein the framecomprises a moisture barrier.
 40. The caulkless panelized wall system ofclaim 21, wherein the frame comprises a water break.